"To be in the mood for packing" is a Russian idiom, meaning that one feels that their sojourn someplace won't last long and that they are ready to move on to another place.
When the Soviet troops took their stand on the territory of Eastern Prussia, this region was regarded as German by both the government and the new immigrant residents. The official status of the Kaliningrad region was not defined for a long time. The lack of information produced various rumors about the future of the region:

…There wasn't any confidence that this territory would remain ours. Large-scale construction did not been begin until the 1960s, as we had no idea what would happen to this place. I heard that William Peak was pressing for the return of Prussia to the German Democratic Republic, when Valter Ulbricht gave up on this.

This uncertainty is alao recorded in another way; many families of immigrants still keep pictures on the reverse sides of which you can find the inscription: "In memory of our sojourn in Eastern Prussia."

Some "rudiments" of this uncertainty caused by the way we obtained this land may still be traced in Kaliningraders' consciousness:

…What is your view of the future of Kaliningrad? Will we be pushed out of Russia or will our territory belong to Russia while being simultaneously integrated into Europe, or will this region become an inconsumable "aircraft-carrier"? I wonder how our Motherland sees it.

…"Will we be sold to Germany?" Mr. Putin was asked this question by a student during an unprecedented presidential talk with the entire country. This student is an example of mythologized consciousness typical of average residents of the Kaliningrad region.

…The West has enough time at its disposal to tear this land away from Russia by means of gradual economic and cultural integration of the region into Europe. It is reminiscent of a cuttlefish slowly swallowing a worm and digesting it.

…Strange as it may seem, talks about possible German claims for the western and the smallest Russian subject (15 000 km2) are encouraged, intentionally or not, by some Russian politicians…